Conversion coating solution for treating metal surfaces

摘要

A conversion coating, predominantly consisting of tin phosphate, can be deposited on steel or tin plated steel surfaces by contact with a solution containing phosphate ions, tin ions, an oxidizing agent such as chlorate, and a chelating agent for the tin ions, the latter to prevent the rapid loss of tin from the solution that otherwise would occur. A coating that confers excellent resistance to corrosion in hot water is formed on drawn and ironed thinly tin plated cans.